MCH is a hypothalamus-derived hormone known to have an appetite increasing action. Furthermore, it has been reported that MCH knockout mouse behaves normally but shows a significantly decreased food ingestion amount and a lighter body weight as compared to normal mouse (Nature, vol. 396, page 670, 1998). Therefrom MCH receptor antagonists are expected to be superior appetite suppressants or anti-obesity agents.
As compounds having a MCH receptor antagonistic action, the following compounds are known.
1) WO01/21577 (patent document 1) discloses a melanin-concentrating hormone antagonist comprising a compound represented by the formula:
whereinAr1 is a cyclic group optionally having substituent(s);X is a spacer with a main chain having an atom number of 1 to 6;Y is a bond or a spacer with a main chain having an atom number of 1 to 6;Ar is a monocyclic aromatic ring optionally condensed with a 4- to 8-membered nonaromatic ring and further optionally having substituent(s);R1 and R2 are the same or different and each is a hydrogen atom or a hydrocarbon group optionally having substituent(s), R1 and R2 may form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s), R2 forms a Spiro ring together with Ar, or R2 may form, together with the adjacent nitrogen atom and Y, a nitrogen-containing heterocycle optionally having substituent(s),or a salt thereof.2) WO01/82925 (patent document 2) discloses a melanin-concentrating hormone antagonist comprising a compound represented by the formula:
whereinAr1 is a cyclic group optionally having substituent(s);X and Y are the same or different and each is a spacer with a main chain having an atom number of 1 to 6;Ar is a condensed polycyclic aromatic ring optionally having substituent(s);R1 and R2 are the same or different and each is a hydrogen atom or a hydrocarbon group optionally having substituent(s), R1 and R2 may form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s), R2 may form, together with the adjacent nitrogen atom and Y, nitrogen-containing heterocycle optionally having substituent(s), or R2 may form, together with the adjacent nitrogen atom, Y and Ar, a nitrogen-containing fused ring optionally having substituent(s),or a salt thereof.3) WO01/87834 (patent document 3) discloses a melanin-concentrating hormone antagonist comprising a compound represented by the formula:
whereinR is a hydrogen atom, a halogen atom or a cyclic group optionally having substituent(s);X is a bond or a spacer with a main chain having an atom number of 1 to 10;Y is a spacer with a main chain having an atom number of 1 to 6;ring A is a benzene ring further optionally having substituent(s);ring B is 5- to 9-membered nitrogen-containing nonaromatic heterocycle further optionally having substituent(s);R1 and R2 are the same or different and each is a hydrogen atom, a hydrocarbon group optionally having substituent(s) or a heterocyclic group optionally having substituent(s), R1 and R2 may form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s), or R2 may form, together with the adjacent nitrogen atom and Y, nitrogen-containing heterocycle optionally having substituent(s),or a salt thereof.4) WO03/035624 (patent document 4) discloses a compound represented by the formula:
whereinAr is a cyclic group optionally having substituent(s);X is a bond or a spacer with a main chain having an atom number of 1 to 6;R1 and R2 are the same or different and each is a hydrogen atom or a hydrocarbon group optionally having substituent(s),R1 and R2 may form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s);Y is a divalent hydrocarbon group optionally having substituent(s) (excluding CO);R3 is a hydrogen atom or a hydrocarbon group optionally having substituent(s); andring A and ring B may further have substituent(s), and when ring B further has substituent(s), the substituent(s) may be bonded to R1 to form a ring,or a salt thereof or a prodrug thereof.5) WO2004/072018 (patent document 5) discloses a compound represented by the formula:
whereinAr1 is a cyclic group optionally having substituent(s); R is a hydrogen atom, optionally halogenated C1-6 alkyl, phenyl optionally having substituent(s) or pyridyl optionally having substituent(s);Ra1, Ra2, Ra3 and Ra4 are the same or different and each is a hydrogen atom, optionally halogenated C1-6 alkyl, phenyl optionally having substituent(s), a halogen atom, pyridyl optionally having substituent(s), cyano, optionally halogenated C1-6 alkoxy, optionally halogenated C1-6 alkylthio, amino, mono- or di-C1-6 alkylamino, formyl, optionally halogenated C1-6 alkyl-carbonyl or optionally halogenated C1-6 alkylsulfonyl;Ar is a monocyclic aromatic ring optionally having substituent(s);Y is an optionally halogenated alkylene group;(1) R1 and R2 are the same or different and each is a hydrogen atom or C1-6 alkyl, (2) R1 and R2 form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s), (3) R1 and Y form, together with the adjacent nitrogen atom, nitrogen-containing heterocycle optionally having substituent(s), and R2 is a hydrogen atom or C1-6 alkyl, provided that when the nitrogen-containing heterocycle formed by R1 and R2 together with the adjacent nitrogen atom is piperazine or when R is C1-4 alkyl, then Ar1 is a cyclic group having substituent(s), or a salt thereof.6) WO2006/118320 (patent document 6) discloses a compound represented by the formula:
whereinAr is an optionally substituted ring;A is a spacer with a main chain having an atom number of 1 to 4;B is a bond, a C1-10 alkylene group or an oxygen atom;R3 and R5 are each independently a hydrogen atom or a substituent;R4 is an optionally substituted cyclic group or an optionally substituted C1-10 alkyl group;R1 and R2 are each independently a hydrogen atom or a substituent, R1 is bonded to R2 or B to form optionally substituted nitrogen-containing heterocycle, or R1 is bonded to Ar to form optionally substituted nitrogen-containing fused heterocycle,or a salt thereof.7) JP-A-2008-88120 (patent document 7) discloses a compound represented by the formula:
whereinR1 is an optionally substituted C1-6 alkoxy group;R2 is a hydrogen atom, a methyl group or a halogen atom;X is a C4-7 hydrocarbon group substituted by a hydroxy group or an oxo group,or a salt thereof.8) WO2009/123194 (patent document 8) discloses a compound represented by the formula:
whereinring A is a 6-membered ring further optionally substituted;R1 is a hydrogen atom, a halogen atom or a C1-6 alkyl group;R2 is a hydrogen atom or a C1-6 alkyl group;R3 is a group represented by the formula: —Y—S(O)m1—R4a whereinY is a bond or NH; m1 is an integer of 1 or 2; R4a is a C1-6 alkyl group optionally substituted by 1 to 3 halogen atoms, or a cyclic group represented by the formula:
wherein m2, m3, m4, n1, n2 and n3 are independently an integer of 1 or 2; R4b is a C1-6 alkyl group optionally substituted by 1 to 3 halogen atoms (the ring moiety of the cyclic group is optionally further substituted);R5 is a 5- or 6-membered cyclic group optionally further substituted;X1 is a bond or a C1-6 alkylene group; andX2 is a bond or a C1-6 alkylene group,or a salt thereof.